Operating experience with lined cyclones in vessels with a fluidized bed

This paper is concerned with the wear of cyclones in vessels with a fluidized bed which generally show up as severe erosion and loss of finely dispersed material, resulting in pollution of the environment and breakdown of the equipment. Improved efficiency and longer life of the dust collection system are particularly important objectives in the case of units operating with expensive, finely dispersed catalysts. Cyclones are fabricated of comparatively thin sheet steel; the sections that are subject to severe erosion are protected with hard-facing or coatings of various materials, including nonmetallic heat-resistant coatings. In order to evaluate the operating capabilities of certain lining materials, to work out the procedures for application of these materials, and to select the design for the reinforcing elements, the authors prepared three single-stage cyclones for lining; these cyclones were designed for use in the reactors of a large semicommercial process unit for fluid coking and pyrolysis at the Kuibyshev refinery. Experimental data are presented which show that the concrete based on orthophosphoric acid with corundum filler gave reliable protection of the cyclone surfaces against erosion. The lining mix can be prepared and applied to the surface under refinery conditions, using available equipment, by workers trained at an intermediate level of qualification.